blood pressure monitor

Abstract

To enable both blood pressure measurement and atrial fibrillation determination while reducing a burden on a user.SOLUTION: A sphygmomanometer 20 measures blood pressure of a user on the basis of a pulse wave signal superposed on a cuff pressure signal detected in the process of pressurizing or depressurizing cuff pressure indicating inner pressure of a cuff worn on a measurement part of the user. The sphygmomanometer 20 includes a storage part for acquiring pulse wave feature information indicating a feature amount of a pulse wave from the pulse wave signal superposed on the cuff pressure signal detected in the blood pressure measurement for each blood pressure measurement, and storing the acquired pulse wave feature information for each blood pressure measurement, a number-of-pulse-waves determination part for determining the number of pulse waves having the feature amount indicated by the pulse wave feature information on the pulse wave feature information for each blood pressure measurement, and an atrial fibrillation determination part for determining atrial fibrillation in the pulse waves on the basis of the pulse wave feature information in the storage part when the sum total of the number of pulse waves for each blood pressure measurement reaches a predetermined number.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a sphygmomanometer, and more particularly to a sphygmomanometer having a function of determining atrial fibrillation.

Background Art

[0002] Early detection of atrial fibrillation, which causes heart disease, is desired. Conventionally, a technique for estimating atrial fibrillation from pulse wave information obtained by a household electronic sphygmomanometer has been proposed. Specifically, in one measurement opportunity using an electronic sphygmomanometer, for example, blood pressure measurements are continuously performed a plurality of times, and the pulse wave interval, which is the interval between the pulse wave signals obtained in each blood pressure measurement, is obtained, and atrial fibrillation is detected based on the pulse wave interval.

[0003] For example, U.S. Patent Application Publication No. 2016 / 0228017 (Patent Document 1) discloses a blood pressure measuring device capable of indicating the presence or absence of atrial fibrillation.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the device disclosed in Patent Document 1, in order to determine the presence or absence of atrial fibrillation, three consecutive blood pressure measurements are required in one measurement opportunity. Always measuring blood pressure three times consecutively every measurement opportunity is a burden on the user, such as increasing the time required for measurement and causing a sense of restraint to the user due to compression of the measurement site by the cuff.

[0006] The present disclosure is to provide a sphygmomanometer that enables both blood pressure measurement and atrial fibrillation determination while reducing the burden on the user. [Means for solving the problem]

[0007] The blood pressure monitor according to this disclosure includes: a cuff pressure adjustment unit that increases or decreases cuff pressure, which indicates the internal pressure of a cuff attached to the user's measurement site; a cuff pressure detection unit that detects a cuff pressure signal indicating cuff pressure; a blood pressure measurement unit that measures the user's blood pressure based on a pulse wave signal superimposed on the cuff pressure signal detected during the process of increasing or decreasing cuff pressure; an information acquisition unit that acquires pulse wave feature information representing the characteristic quantities of a pulse wave from the pulse wave signal superimposed on the cuff pressure signal detected in each blood pressure measurement; a storage unit that stores the acquired pulse wave feature information for each blood pressure measurement; a pulse count determination unit that determines the number of pulse waves having the characteristic quantities represented by the pulse wave feature information for each blood pressure measurement; and an atrial fibrillation determination unit that determines atrial fibrillation in the pulse wave based on the pulse wave feature information in the storage unit when the total number of pulse waves for each blood pressure measurement reaches a predetermined number.

[0008] According to the disclosure described above, atrial fibrillation in the pulse wave is determined based on the pulse wave characteristic information in the storage unit when the total number of pulse waves for each blood pressure measurement reaches a predetermined number. This eliminates the need to perform multiple blood pressure measurements to determine atrial fibrillation during a single blood pressure measurement opportunity. As a result, it is possible to achieve both blood pressure measurement and atrial fibrillation determination while reducing the burden on the user, such as the user's measurement site being repeatedly compressed multiple times and the blood pressure measurement time being prolonged.

[0009] The pulse rate determination unit in the blood pressure monitor described above determines the number of pulse waves for each blood pressure measurement by excluding pulse wave characteristic information corresponding to blood pressure measurements where the elapsed time since the blood pressure measurement was performed is greater than or equal to a threshold, from the pulse wave characteristic information for each blood pressure measurement.

[0010] According to the blood pressure monitor mentioned above, it is possible to exclude old, past pulse wave characteristic information from the pulse wave characteristic information used to determine atrial fibrillation.

[0011] In the blood pressure monitor described above, the pulse wave feature quantities represented by the pulse wave characteristic information include the interval between pulse waves indicated by the pulse wave signal superimposed on the cuff pressure signal detected during blood pressure measurement.

[0012] According to the blood pressure monitor mentioned above, the pulse wave interval can be included in the pulse wave characteristics used to determine atrial fibrillation.

[0013] In the blood pressure monitor described above, the interval between pulse waves includes the time interval between the maximum amplitudes of adjacent pulse waves.

[0014] According to the blood pressure monitor mentioned above, the interval of the pulse wave can include the time interval of the maximum amplitude.

[0015] In the blood pressure monitor mentioned above, pulse rate The determination unit excludes pulse wave feature information corresponding to pulse waves whose amplitude is below a threshold and possesses the feature quantities represented by the pulse wave feature information for each blood pressure measurement, and determines the number of pulse waves for each blood pressure measurement.

[0016] According to the blood pressure monitor described above, pulse wave feature information corresponding to pulse waves with amplitudes below a threshold can be excluded from the pulse wave feature information used to determine atrial fibrillation.

[0017] In the blood pressure monitor described above, the pulse rate determination unit further determines whether the total number of pulse waves corresponding to the pulse wave characteristic information for each blood pressure measurement in the storage unit has reached a predetermined number.

[0018] According to the blood pressure monitor described above, when the pulse rate determination unit determines that the total number of pulse waves corresponding to the pulse wave characteristic information for each blood pressure measurement stored in the storage unit has reached a predetermined number, it can determine atrial fibrillation in the pulse wave based on the pulse wave characteristic information stored in the storage unit. [Effects of the Invention]

[0019] This disclosure enables both blood pressure measurement and atrial fibrillation detection while reducing the burden on the user. [Brief explanation of the drawing]

[0020] [Figure 1] FIG. 1 is a diagram showing an example of a network configuration to which the blood pressure measurement system according to the present embodiment is applied. [Figure 2] FIG. 4 is a block diagram showing an example of the hardware configuration of the sphygmomanometer 20 according to the present embodiment. [Figure 3] FIG. 7 is a diagram showing an example of the functional configuration of the sphygmomanometer 20 according to the present embodiment. [Figure 4] FIG. 10 is a flowchart showing an example of the process related to the measurement of the sphygmomanometer 20 according to the present embodiment. [Figure 5] FIG. 13 is a flowchart showing an example of the blood pressure measurement process of FIG. 4. [Figure 6] FIG. 16 is a diagram showing an example of the information display on the display 31 according to the present embodiment. [Figure 7] FIG. 19 is a diagram showing an example of the information display on the display 31 according to the present embodiment. [Figure 8] FIG. 22 is a diagram showing an example of a plurality of pulse waves used for AF determination according to the present embodiment. Embodiments of the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0022] <Application Example> Referring to FIG. 3, an application example of the sphygmomanometer according to the present embodiment will be described. FIG. 3 is a diagram showing an example of the functional configuration of the sphygmomanometer 20 according to the present embodiment. Hereinafter, atrial fibrillation will be referred to as AF.

[0023] The sphygmomanometer 20 according to the present embodiment is configured to measure blood pressure by pressurizing or depressurizing the cuff pressure indicating the internal pressure of a cuff (air bag) wrapped around a user's measurement site, for example, the arm. Note that the measurement site is not limited to the upper arm.

[0024] Referring to Figure 3, the blood pressure monitor 20 includes, as its main functional components, a blood pressure measurement unit 220, an AF determination unit 230, an output control unit 240 that controls the output of information, and a storage control unit 250 that controls the reading and writing of information to the memory unit 36. Each of these units is realized, for example, by the blood pressure monitor 20's processor 30 reading a program stored in the storage 35 (described later), and then expanding and executing the read program in the memory 33 (described later). Note that some or all of these units may be implemented using hardware circuits including an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

[0025] The memory unit 36 ​​is configured to include a storage 35 or a memory 33, which will be described later. The memory unit 36 ​​includes a working memory area 361, which is mainly composed of a volatile storage medium, and an information memory area. This information memory area stores information including interval information 362, blood pressure measurement information 363, which shows the measured blood pressure information, and AF judgment information 364, which shows the AF judgment result. The interval information 362 indicates the pulse wave interval, which is an example of the pulse wave feature quantities detected in time series from the measurement site during blood pressure measurement.

[0026] The blood pressure measurement unit 220 controls the cuff pressure based on a pulse wave signal superimposed on a cuff pressure signal indicating the cuff pressure detected by the pressure sensor 22, in accordance with instructions given by the user's operation to the blood pressure measurement unit and blood pressure monitor. Specifically, the blood pressure measurement unit 220 controls the pump 23 via the pump drive circuit 26 and the valve 24 via the valve drive circuit 27. The valve 24 is opened and closed to control the cuff pressure by releasing or sealing air in the fluid bag.

[0027] The blood pressure measurement unit 220 receives a cuff pressure signal detected by the pressure sensor 22 and extracts a pulse wave signal representing the pulse wave of the area being measured, which is superimposed on the cuff pressure signal. That is, the blood pressure measurement unit 220 detects a time-series pulse wave from the cuff pressure signal, which is a pressure component superimposed on the cuff pressure signal in synchronization with the user's heartbeat. The analog pulse wave signal measured by the pressure sensor 22 is converted into digital pulse wave information. The interval calculation unit 221 of the blood pressure measurement unit 220 calculates the interval between adjacent pulse waves in the time-series pulse wave that constitutes the pulse wave information. For each pair of two adjacent pulse waves in the time-series pulse wave, the interval calculation unit 221 generates interval information 362 that indicates the interval between the adjacent pulse waves constituting the pair, in association with the pair. The interval information 362 is stored in the storage unit 36 ​​by the storage control unit 250. In this embodiment, the interval between pulse waves is, for example, the time from the time when the peak with the maximum amplitude of the pulse wave signal is detected to the time when the peak of the next pulse wave signal's amplitude is detected.

[0028] The interval calculation unit 221 is an embodiment of the "information acquisition unit" that acquires characteristic quantities of the pulse wave. 3 In this example, the interval calculation unit 221 is shown as a function included in the blood pressure measurement unit 220, but it may also be provided as a function independent of the blood pressure measurement unit 220. Furthermore, while the feature quantity is shown as the pulse wave interval, it is not limited to intervals.

[0029] The blood pressure measurement unit 220 calculates blood pressure measurement information 363 representing the user's blood pressure based on the pulse wave signal. The blood pressure measurement information 363 is stored in the storage unit 36 ​​and output as a measurement result to the output control unit 240. Specifically, in blood pressure measurement, the cuff pressure is increased to a predetermined pressure, and based on the pulse wave signal detected during the subsequent decompression process, the blood pressure measurement unit 220 measures the user's blood pressure according to the oscillometric method, outputs the measurement result to the output control unit 240, and stores the blood pressure measurement information 363, including the measurement result, in the storage unit 36 ​​via the storage control unit 250. Typically, the blood pressure measurement information 363 calculated by the blood pressure measurement unit 220 includes systolic blood pressure, diastolic blood pressure, and pulse rate.

[0030] In the AF determination process performed by the AF determination unit 230, the pulse count determination unit 232 analyzes the interval information 362 stored in the memory unit 36 ​​and, based on the analysis results, determines whether the number of pulse waves corresponding to the interval information 362 has reached a predetermined number. In response to the pulse count determination unit 232 determining that the number of pulse waves corresponding to the interval information 362 has reached a predetermined number, the AF determination unit 230 performs a predetermined process based on the interval information 362 corresponding to the predetermined number of pulse waves in the memory unit 36 ​​to determine the presence or absence of AF in the pulse wave. The above predetermined process is a process for detecting AF, and for example, the presence or absence of AF is determined using a pattern of pulse wave intervals. In the pulse wave signal, the amplitude peak (maximum point) for each beat is detected, and the time interval between the peaks of the current beat and the previous beat is calculated as the pulse wave interval. Note that the interval used for determination is not limited to the peak interval, but may also be the interval between the rising points of adjacent pulse waves.

[0031] The result of the AF determination process described above is output to the output control unit 240, and the AF determination information 364 indicating the determination result is stored in the storage unit 36.

[0032] The output control unit 240 generates display data for displaying blood pressure values ​​and AF judgment results based on the measurement results from the blood pressure measurement unit 220 and the judgment results from the AF judgment unit 230, and outputs it to the display control circuit 31A. The display control circuit 31A drives the display 31 based on this display data, thereby displaying the blood pressure values ​​and AF judgment information on the display 31.

[0033] Furthermore, in the AF determination process, the selection unit 231 of the AF determination unit 230 selects a set of pulse waves that allows for highly accurate determination of AF. Specifically, for each of the multiple sets of pulse waves indicated by the interval information 362 stored in the memory unit 36, the selection unit 231 deletes from the interval information 362 any sets of pulses corresponding to blood pressure measurements where the elapsed time since the measurement of the pulse wave (blood pressure measurement date and time) is greater than or equal to a threshold.

[0034] Furthermore, in the AF determination process, the selection unit 231 compares the peak value of the amplitude of each of the multiple sets of pulse waves indicated by the interval information 362 stored in the storage unit 36 ​​with a threshold value. Based on this comparison result, the selection unit 231 detects sets of pulse waves having amplitudes corresponding to peak values ​​less than the threshold value and deletes the detected sets from the interval information 362.

[0035] After the selection unit 231 selectively deletes such sets of pulse waves, the pulse count determination unit 232 and the AF determination unit 230 process the remaining interval information 362. This eliminates pulse waves from older measurement dates or pulse waves with insufficient amplitude from the pulse wave information used for AF determination. Therefore, this prevents these information from acting as noise and improves the accuracy of AF determination. The method for selecting the pulse waves to be deleted may be based on the elapsed time since measurement, or on the amplitude of the pulse wave signal, or both may be performed.

[0036] According to the blood pressure monitor 20 described above, when the total number of pulse waves acquired with each blood pressure measurement reaches a predetermined number, an AF (Atrial Fatigue) determination is performed based on interval information 362 corresponding to that predetermined number of pulse waves stored in the memory unit 36. Thus, the trigger for the AF determination is not the number of blood pressure measurements, but the total number of pulse waves acquired through the measurements reaching a predetermined number. Therefore, unlike Patent Document 1, it is not necessary to always perform three consecutive blood pressure measurements for AF determination, thus reducing the burden on the user.

[0037] <Network Configuration> Figure 1 shows an example of a network configuration to which the blood pressure monitor 20 according to this embodiment is applied. Referring to Figure 1, the network system 1 includes a blood pressure monitor 20, a server 40, and portable information processing terminals 10A and 10B, such as smartphones, all of which are connectable to the network. The blood pressure monitor 20 communicates with terminal 10A via network 10. Terminals 10A and 10B communicate with server 40 via network 15. Information measured by the blood pressure monitor 20 may be transferred to server 40 and stored in database 42. Networks 10 and 15 are composed of various communication networks such as Wi-Fi®, mobile communication networks, and the Internet.

[0038] The blood pressure monitor 20 may include different types of blood pressure monitors 20A, 20B, and 20C. Blood pressure monitor 20 is a stationary upper arm blood pressure monitor in which the main unit and cuff 21 are separate. Blood pressure monitor 20B is a wrist-worn type blood pressure monitor in which the main unit and cuff are integrated. Blood pressure monitor 20C is constructed with the cuff and main unit integrated and is worn, for example, on the upper arm. Hereinafter, for convenience of explanation, blood pressure monitors 20A, 20B, and 20C may be collectively referred to as "blood pressure monitor 20". Any type of blood pressure monitor is configured to perform the blood pressure measurement and AF determination described above. In this embodiment, blood pressure monitor 20A will be used as an example for explanation.

[0039] Terminals 10A and 10B are, for example, smartphones having touch panels that constitute a display. Terminal 10A receives measurement information from the blood pressure monitor 20, displays the received measurement information on its display, and also transfers the received measurement information to the server 40 for storage in the database 42. Terminal 10B communicates with the server 40 to receive measurement information retrieved from the database 42 and displays it on its display. Even if the blood pressure monitor 20 is a stationary type, the user can obtain information measured by the blood pressure monitor 20 using the portable terminals 10A and 10B.

[0040] In this embodiment, the functions shown in Figure 3 are implemented in the blood pressure monitor 20, but the implementation method is not limited to this. For example, the system may be composed of multiple devices such as the blood pressure monitor 20 and a server 40 or terminals 10A and 10B working together. When multiple devices work together in this way, the processing that realizes the functions of the blood pressure measurement system can be realized by distributed processing among these multiple devices. As for distributed processing, for example, among the functions of the blood pressure monitor 20 in Figure 3, the AF determination unit 230 may be implemented in terminal 10A or server 40. Also, the storage unit 36 ​​may be configured in the database 42 of server 40 or in terminals 10A and 10B. Note that the distribution method is not limited to this.

[0041] <Hardware Configuration> Figure 2 is a block diagram showing an example of the hardware configuration of the blood pressure monitor 20 according to this embodiment. Referring to Figure 2, the blood pressure monitor 20 includes, as its main components, a main body and a cuff 21. The cuff 21 contains an air fluid bag. The main body includes a processor 30, an air system component constituting a "cuff pressure adjustment unit" for blood pressure measurement, an A / D conversion circuit 25, a pump drive circuit 26, a valve drive circuit 27, a display 31 to which a display control circuit 31A is connected, a storage unit 36, an operation unit 32 that receives user operations for the blood pressure monitor 20, a communication interface 28 that enables communication of the blood pressure monitor 20 to a network, a reader / writer 29 to which a non-volatile storage medium such as a memory card 29A is detachably attached, and a power supply 34.

[0042] The processor 30 comprises arithmetic processing circuits such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit). The processor 30 performs processing for the blood pressure monitor 20 by reading and executing a program from the memory unit 36. For example, the processor 30 controls the pump 23 and valve 24 in response to operation signals from the operation unit 32. The processor 30 also calculates blood pressure values ​​using an algorithm for blood pressure calculation using the oscillometric method and displays them on the display 31.

[0043] The storage unit 36 ​​includes a non-volatile storage medium such as an HDD (Hard Disk Drive) 35 and a memory 33. The memory 33 includes a volatile or non-volatile storage medium. The memory 33 includes, for example, RAM (Random Access Memory), ROM (Read-Only Memory), and flash memory. The storage unit 36 ​​stores a program for controlling the blood pressure monitor 20, data used to control the blood pressure monitor 20, setting data for setting various functions of the blood pressure monitor 20, and information on the measurement results of blood pressure values. The memory 33 is also used as work memory for the processor 30 to expand and execute the program read from the storage unit 36.

[0044] The air system component increases or decreases the cuff pressure, which indicates the internal pressure of the cuff 21 attached to the user's measurement site. Specifically, the air system component includes a pressure sensor 22 for detecting the cuff pressure, which is the pressure inside the fluid bag, and a pump 23 and valve 24 as an inflation / deflation mechanism for inflating and deflating the fluid bag, so that air can be supplied to or discharged from the fluid bag enclosed in the cuff 21 through an air pipe.

[0045] The pressure sensor 22 detects the pressure inside the fluid bag (cuff pressure) and outputs a signal (cuff pressure signal) corresponding to the detected pressure to the A / D conversion circuit 25. The pressure sensor 22 is, for example, a piezoresistive pressure sensor and is fluidically connected to the pump 23, valve 24, and the fluid bag enclosed in the cuff 21 via air piping. The pump 23 supplies air as a fluid to the fluid bag via the air piping to pressurize the cuff pressure. The valve 24 is opened and closed to control the cuff pressure by discharging air from inside the fluid bag via the air piping or by sealing air into the fluid bag.

[0046] The A / D conversion circuit 25 converts the output value of the pressure sensor 22 (e.g., electrical resistance) from an analog signal to a digital signal and outputs it to the processor 30. In this example, the processor 30 acts as an oscillator circuit that oscillates at a frequency corresponding to the change in electrical resistance due to the piezoresistive effect from the pressure sensor 22, and acquires a signal representing the cuff pressure according to its oscillation frequency. The pump drive circuit 26 controls the drive of the pump 23 based on a control signal provided by the processor 30. The valve drive circuit 27 controls the opening and closing of the valve 24 based on a control signal provided by the processor 30.

[0047] When measuring blood pressure using the oscillometric method, the following operations generally occur. Specifically, a cuff 21 is wrapped around the user's (subject's) measurement site (wrist, arm, etc.) in advance, and during measurement, the pump 23 and valve 24 are controlled to pressurize the cuff 21. During this pressurization process, when the cuff pressure reaches a predetermined pressure Cp, the pump 23 stops and the valve 24 is controlled to gradually open. This reduces the cuff pressure. During this depressurization process, fluctuations in arterial volume occurring in the artery at the measurement site are extracted as a pulse wave signal superimposed on the cuff pressure signal. Based on the changes in the amplitude of the pulse wave signal (mainly the rise and fall) accompanying the change in cuff pressure during the depressurization process, the systolic blood pressure and diastolic blood pressure are calculated. Note that this type of blood pressure measurement is not limited to cases performed during the depressurization process, but may also be performed using the pulse wave signal superimposed on the cuff pressure signal detected during the pressurization process.

[0048] The control unit 32 receives user input to the blood pressure monitor 20 and outputs an operation signal to the processor 30 indicating the received user input. The processor 30 outputs commands to each unit based on the operation signal. The control unit 32 includes a measurement switch 32A which is operated to instruct the start of blood pressure measurement. The control unit 32 may include other types of switches or buttons.

[0049] When the measurement switch 32A is operated, the processor 30 controls the air system components so that the measurement site is compressed by the cuff 21, and calculates the blood pressure value according to the oscillometric method. If the measurement switch 32A is operated again while such blood pressure measurement is being performed, the processor 30 stops the blood pressure measurement.

[0050] The reader / writer 29 reads a program or data from the inserted memory card 29A. The processor 30 stores the read program or data in the storage unit 36. The reader / writer 29 also writes information such as measurement results read from the storage unit 36 ​​by the processor 30 to the inserted memory card 29A.

[0051] The display 31 displays various information, including blood pressure measurement results and AF judgment information, based on display data from the display control circuit 31A. The communication interface 28 is configured, for example, to include a NIC (Network Interface Card) and controls the exchange of information between the blood pressure monitor 20 and other devices (terminals 10A, 10B and server 40). The power supply 34 supplies power to the processor 30 and each piece of hardware.

[0052] <Flowchart and display example> Figure 4 is a flowchart showing an example of the measurement process of the blood pressure monitor 20 according to this embodiment. At the start of this process, the cuff 21 of the blood pressure monitor 20 is attached (wrapped) around the user's measurement site.

[0053] Referring to Figure 4, the processor 30 of the blood pressure monitor 20 receives an operation signal from the operation unit 32 based on user operation of the measurement switch 32A (step S1). In response to the operation signal, the processor 30 starts the blood pressure measurement process (step S2). During this blood pressure measurement process, interval information 362 is stored in the storage unit 36. Details of the blood pressure measurement process will be described later.

[0054] The processor 30 detects the number of pulse waves corresponding to the interval information 362 stored in the memory unit 36 ​​and determines whether the number of detected pulse waves has reached a predetermined number (step S4). If the processor 30 determines that the number of pulse waves has reached a predetermined number (YES in step S4), it performs the AF determination process described above (step S5). In the AF determination process of step S5, the processor 30 extracts interval information corresponding to the predetermined number of pulse waves from the interval information 362 in the memory unit 36 ​​and determines whether or not AF is present in the pulse wave based on the extracted interval information.

[0055] The processor 30 displays the result of the AF determination in step S5. I3 Display data to be displayed on 1 is output to the display control circuit 31A (step S6).

[0056] On the other hand, the processor 30 has reached a predetermined number of pulse waves. and If no determination is made (NO in step S4), the AF determination process in step S5 and the display of the determination result (steps S5 and S6) are not performed, and the process ends.

[0057] Figure 5 is a flowchart showing an example of the blood pressure measurement process in Figure 4. In Figure 5, the processor 30 turns off (stops) the pump 23 and opens the valve 24, then initializes the pressure sensor 22 (step S21). During the initialization of the pressure sensor 22, the current output value of the pressure sensor 22 is set to a value equivalent to atmospheric pressure. In step S21, the processor 30 initializes the working memory area 361 of the storage unit 36.

[0058] The processor 30 closes the valve 24 via the valve drive circuit 27 (step S22). Subsequently, the processor 30 turns on (starts) the pump 23 via the pump drive circuit 26 and starts pressurizing the cuff 21 (fluid bag) at a predetermined pressurizing speed (step S23).

[0059] The processor 30 compares the cuff pressure indicated by the cuff pressure signal detected by the pressure sensor 22 with a predetermined pressure Cp, and determines whether the cuff pressure has reached the predetermined pressure Cp based on the comparison result (step S24). If it is determined that the cuff pressure has not reached the predetermined pressure Cp (NO in step S24), the process returns to step S23 and the cuff 21 is pressurized at a predetermined pressurizing rate.

[0060] When it is determined that the cuff pressure has reached a predetermined pressure Cp (YES in step S24), the processor 30 turns off (stops) the pump 23 via the pump drive circuit 26 (step S25). Subsequently, the processor 30 gradually opens the valve 24 via the valve drive circuit 27 so that the cuff pressure indicated by the cuff pressure signal detected by the pressure sensor 22 is reduced at a predetermined rate (step S26).

[0061] During the decompression process in which the pressure is reduced at a predetermined rate, the processor 30 extracts a pulse wave signal from the cuff pressure signal detected by the pressure sensor 22, and attempts to calculate the maximum blood pressure (systolic blood pressure) and minimum blood pressure (diastolic blood pressure) based on the extracted pulse wave signal, and determines whether the blood pressure calculation is complete or not (step S28). The processor 30 stores the pulse wave signal detected during the decompression process in the working memory area 361. If the processor 30 determines, based on the pulse wave signal stored in the working memory area 361, that it is not yet possible to complete the blood pressure calculation, such as when a sufficient pulse wave signal has not been obtained (NO in step S28), the processor 30 returns to step S26. If it is determined that the blood pressure calculation is complete (YES in step S28), the processor 30 sets the valve 24 to fully open via the valve drive circuit 27 so that the air in the cuff 21 is rapidly exhausted (step S29). The processor 30 displays the blood pressure value (measurement result) measured in step S27 on the display 31 (step S30). Furthermore, the blood pressure measurement information 363, which indicates the blood pressure value (measurement result), is stored in the memory unit 36.

[0062] The processor 30 calculates the intervals between the pulses for each set of a plurality of pulses indicated by the pulse wave signal stored in the working memory area 361 (step S31), and stores the interval information 362 indicating the calculated intervals for each set in the storage unit 36 (step S32).

[0063] As described above, in this embodiment, for each blood pressure measurement, interval information 362 is acquired for a plurality of pulse waves corresponding to the pulse wave signal used for calculating the blood pressure. As a result, the interval information 362 acquired for each blood pressure measurement is stored in the storage unit 36 in association with the measurement date and time of the corresponding blood pressure measurement.

[0064] FIG. 6 and FIG. 7 are diagrams showing examples of information display on the display 31 according to this embodiment. FIG. 6 shows an example of display when it is determined that there is AF in a case where the AF determination process (step S5) is performed after the blood pressure measurement (step S2). In FIG. 6, the results of the blood pressure measurement (systolic blood pressure SYS, diastolic blood pressure DIA, pulse rate PLS) and a message 311 indicating that it is determined that there is AF are displayed.

[0065] On the other hand, FIG. 7 shows an example of display in a case where the AF determination process (step S5) is not performed after the blood pressure measurement (step S2), or in a case where the AF determination process (step S5) is performed after the blood pressure measurement (step S2) and it is determined that "there is no AF". In FIG. 7, only the results of the blood pressure measurement (systolic blood pressure SYS, diastolic blood pressure DIA, pulse rate PLS) are displayed, and the determination result of AF is not displayed. In a case where the AF determination process (step S5) is performed after the blood pressure measurement (step S2) and it is determined that "there is no AF", a message indicating "there is no AF" may be displayed on the screen of FIG. 7.

[0066] <Example of AF determination> FIG. 8 is a diagram showing an example of a plurality of pulse waves used for AF determination according to this embodiment. In this embodiment, the interval information 362 of the pulse waves acquired in each of a plurality of blood pressure measurements is integrated, and AF determination is performed based on the integrated interval information 362.

[0067] In Figure 8, when blood pressure is measured three times during the day—in the morning (7:00), at noon (13:00), and in the evening (23:00)—pulse wave interval information 362 is acquired for each blood pressure measurement and stored in the memory unit 36. In this case, for each of the morning and noon blood pressure measurements, interval information 362 corresponding to each blood pressure measurement is stored in the memory unit 36. When the noon blood pressure is measured, in step S4 of Figure 4, the pulse rate determination unit 232 determines that the number of pulse waves corresponding to the interval information 362 stored in the memory unit 36 ​​has not reached the M number required for AF determination (NO in step S4 of Figure 4), and the AF determination process is not performed. In the subsequent evening blood pressure measurement, interval information 362 corresponding to that blood pressure measurement is stored in the memory unit 36. When blood pressure is measured that evening, in step S4 of Figure 4, the pulse rate determination unit 232 determines that the number of pulse waves corresponding to the interval information 362 stored in the memory unit 36 ​​has reached the M number required for AF determination (YES in step S4 of Figure 4). In other words, the pulse rate determination unit 232 counts the number of pulse waves corresponding to the interval information 362 in the memory unit 36, that is, the total number of pulse waves obtained by integrating the pulse waves acquired in the morning, noon, and evening blood pressure measurements, as (total number = N1 + N2 + N3), and determines that the condition (total number ≥ M) is met (YES in step S4 of Figure 4). Thus, in Figure 8, when the evening blood pressure measurement is performed (step S2 of Figure 4), the AF determination unit 230 integrates the interval information 362 corresponding to the pulse waves (M pulse waves) acquired in each of the morning, noon, and evening blood pressure measurements stored in the memory unit 36, and based on this integrated information, AF determination is performed (step S5 of Figure 4). The M pulse waves mentioned above are composed of multiple pulse waves obtained in one or more blood pressure measurements (step S2 in Figure 4). More specifically, these M pulse waves are composed of multiple pulse waves obtained in one or more blood pressure measurements (step S2 in Figure 4) performed since the previous AF determination process.

[0068] <Advantages of the Embodiment> AF (Atrial Fibrosis) is a disease that causes severe heart disease and requires early treatment. However, many cases are asymptomatic, leading to delays in treatment due to ignorance of the condition. Therefore, routine screening for AF is desirable. Such screening is limited to electrocardiogram (ECG) tests performed by medical institutions, thus limiting opportunities for detecting AF. In contrast, the home blood pressure monitor 20 according to this embodiment utilizes the user's opportunity to measure blood pressure and uses the pulse wave obtained from the measurement to screen (diagnose) AF, thus providing many opportunities for detecting AF. Some AF patients do not always exhibit symptoms of AF, but rather symptoms may appear due to environmental factors such as alcohol consumption, stress, or lack of sleep. Therefore, a mechanism that provides many opportunities for detecting AF, as in this embodiment, can effectively support the decision to initiate treatment in such cases as well.

[0069] Furthermore, the blood pressure monitor 20 according to this embodiment is configured to perform AF determination processing when it is determined that the total number of pulse waves corresponding to the interval information 362 has reached a predetermined number. This configuration eliminates the need to always take three consecutive measurements each time blood pressure is measured, as described in Patent Document 1. As a result, according to this embodiment, the time required for measurement is not increased, and the user is not burdened by repeated compression of the measurement site at a predetermined pressure Cp that is higher than the systolic blood pressure.

[0070] Furthermore, in this embodiment, unlike Patent Document 1, even if three consecutive blood pressure measurements are not required, the selection unit 231 removes information about old past measurement dates or pulse waves with insufficient amplitude from the interval information 362 used for AF determination. This prevents this information from affecting the determination as noise, thereby improving the determination accuracy.

[0071] Furthermore, in this embodiment, since only the pulse wave interval information 362, and not the pulse wave information itself, is stored in the storage unit 36 ​​for AF determination, the memory capacity required to store the information necessary for determination can be saved.

[0072] <Other embodiments> (1) In the above-described embodiment, a program is provided that causes a computer, such as the processor 30 of the blood pressure monitor 20, to execute the processing described in the flowchart above. Such a program can also be provided as a program product by recording it on a non-temporary computer-readable recording medium such as a flexible disk, CD-ROM (Compact Disk Read Only Memory), secondary storage device, main memory, and memory card 29A attached to the computer. Alternatively, such a program can be provided by recording it on a recording medium such as an HDD 35 built into the computer. Furthermore, the program can also be provided to such a computer by downloading it from a distribution server (not shown) via networks 10, 15.

[0073] (2) The configurations illustrated above as embodiments are examples of the present invention and can be combined with other known technologies, and can be modified, such as by omitting parts, without departing from the spirit of the present invention. Furthermore, in the embodiments described above, processes and configurations described in other embodiments may be appropriately adopted and implemented.

[0074] [Note] As described above, this embodiment includes the following disclosures.

[0075] (Composition 1) A cuff pressure adjustment unit (23, 24) that increases or decreases the cuff pressure, which indicates the internal pressure of the cuff attached to the user's measurement site, A cuff pressure detection unit (22) detects a cuff pressure signal indicating the aforementioned cuff pressure, A blood pressure measurement unit (220) measures the user's blood pressure based on a pulse wave signal superimposed on a cuff pressure signal detected during the process of increasing or decreasing the cuff pressure, An information acquisition unit (221) acquires pulse wave characteristic information representing the characteristic quantities of the pulse wave from the pulse wave signal superimposed on the cuff pressure signal detected in the blood pressure measurement for each blood pressure measurement, A storage unit (36) for storing pulse wave characteristic information for each blood pressure measurement obtained, Regarding the pulse wave characteristic information for each blood pressure measurement, a pulse count determination unit (232) determines the number of pulse waves having the characteristic quantity represented by the pulse wave characteristic information, A blood pressure monitor (20) comprising: an atrial fibrillation determination unit (230) that determines atrial fibrillation in the pulse wave based on pulse wave characteristic information of the storage unit when the total number of pulse waves for each blood pressure measurement reaches a predetermined number.

[0076] (Configuration 2) The pulse rate determination unit (232) is, A blood pressure monitor (20) according to configuration 1, which determines the number of pulse waves for each blood pressure measurement by excluding pulse wave characteristic information corresponding to blood pressure measurements where the elapsed time since the blood pressure measurement was performed is greater than or equal to a threshold from the pulse wave characteristic information for each blood pressure measurement.

[0077] (Composition 3) A blood pressure monitor (20) according to configuration 1 or 2, wherein the pulse wave characteristic quantities represented by the pulse wave characteristic information include the interval of the pulse wave indicated by the pulse wave signal superimposed on the cuff pressure signal detected in the blood pressure measurement.

[0078] (Composition 4) The blood pressure monitor (20) according to configuration 3, wherein the interval between pulse waves includes the time interval between the maximum amplitudes of adjacent pulse waves.

[0079] (Composition 5) The pulse rate determination unit is, A blood pressure monitor (20) according to any one of configurations 1 to 4, which determines the number of pulse waves for each blood pressure measurement by excluding pulse wave feature information corresponding to pulse waves whose amplitude has a feature amount represented by the pulse wave feature information for each blood pressure measurement and is below a threshold.

[0080] (Composition 6) The pulse rate determination unit further, A blood pressure monitor (20) according to any one of configurations 1 to 5, which determines whether the total number of pulse waves corresponding to the pulse wave characteristic information for each blood pressure measurement in the storage unit has reached a predetermined number. [Explanation of Symbols]

[0081] 1 Network system, 10,15 Network, 10A,10B Terminal, 20,20A,20B,20C Blood pressure monitor, 21 Cuff, 22 Pressure sensor, 23 Pump, 24 Valve, 25 A / D conversion circuit, 26 Pump drive circuit, 27 Valve drive circuit, 28 Communication interface, 29 Reader / writer, 29A Memory card, 30 Processor, 31 Display, 31A Display control circuit, 32 Operation unit, 32A Measurement switch, 33 Memory, 34 Power supply, 35 Storage, 36 Memory unit, 40 Server, 42 Database, 220 Blood pressure measurement unit, 221 Interval calculation unit, 230 AF determination unit, 231 Selection unit, 232 Pulse rate determination unit, 240 Output control unit, 250 Storage control unit, 311 Message, 361 Working memory area, 362 Interval information, 363 Blood pressure measurement information, 364 judgment information, Cp specified pressure.

Claims

1. A cuff pressure adjustment unit that increases or decreases the cuff pressure, which indicates the internal pressure of the cuff attached to the user's measurement site, A cuff pressure detection unit that detects a cuff pressure signal indicating the aforementioned cuff pressure, A blood pressure measurement unit that measures the user's blood pressure based on a pulse wave signal superimposed on a cuff pressure signal detected during the process of increasing or decreasing the cuff pressure, An information acquisition unit acquires pulse wave characteristic information representing the characteristic quantities of the pulse wave from the pulse wave signal superimposed on the cuff pressure signal detected in the blood pressure measurement for each blood pressure measurement. A storage unit for storing pulse wave characteristic information acquired for each blood pressure measurement, A pulse count determination unit determines the number of pulse waves having the characteristic quantity represented by the pulse wave characteristic information for each blood pressure measurement. A total count determination unit that determines whether the total number of pulse waves obtained by integrating the pulse waves from each blood pressure measurement has reached a predetermined number, Each time the total number is determined to reach a predetermined number, the storage unit determines whether atrial fibrillation is present in the pulse wave based on the pulse wave characteristic information corresponding to the integrated pulse wave, and the unit comprises: The blood pressure monitor includes a total count determination unit that determines whether the total number of pulse waves, which are obtained by integrating the pulse waves determined by the pulse count determination unit for one or more blood pressure measurements since the last time atrial fibrillation was determined, has reached a predetermined number.

2. The pulse rate determination unit is, The blood pressure monitor according to claim 1, wherein the number of pulse waves for each blood pressure measurement is determined by excluding pulse wave characteristic information corresponding to a blood pressure measurement in which the elapsed time since the blood pressure measurement was performed is greater than or equal to a threshold, from the pulse wave characteristic information for each blood pressure measurement.

3. The blood pressure monitor according to claim 1 or 2, wherein the pulse wave feature quantities represented by the pulse wave feature information include the interval of the pulse wave indicated by the pulse wave signal superimposed on the cuff pressure signal detected in the blood pressure measurement.

4. The blood pressure monitor according to claim 3, wherein the interval between pulse waves includes the time interval between the maximum amplitudes of adjacent pulse waves.

5. The pulse rate determination unit is, The blood pressure monitor according to claim 4, wherein the number of pulse waves for each blood pressure measurement is determined by excluding pulse wave feature information corresponding to pulse waves whose amplitude is below a threshold and which have a feature quantity represented by the pulse wave feature information for each blood pressure measurement.

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